The correlation between shifting of the patient's gravity center position and the degree of recovering joint function after total knee arthroplasty

Abstract

To study the correlation between the shifting degree of the gravity center position (GCP) and recovering degree of the knee's function of the patients after total knee arthroplasty (TKA) at the same time point. One hundred and seventy-six patients who underwent single TKA between June 2012 and December 2013 were measured GCP by corresponding instrument prospectively. Ninety-two patients underwent right knee arthroplasty (25 male and 67 female), eighty-four patients underwent left knee arthroplasty (21 male and 63 female). They were evaluated by Hospital For Special Surgery (HSS) scores pre-operatively, 6-month and 1-year post-operatively, and were measured GCP simultaneously. Pearson's correlation analysis were conducted between shifting degree of GCP and changing degree of HSS score when be compared with pre-operatively. All the patient's HSS score had significantly improved at 6-month and 1-year after surgery than pre-operatively (right knee group: t=-42.82 and -62.46, all P=0.00; left knee group: t=-43.10 and -62.82, all P=0.00). HSS scores had been improved from 51.6 ± 4.2 to 76.6 ± 3.6 and 86.5 ± 3.1 in right knee patients, and improved from 52.2 ± 4.5 to 76.0 ± 3.8, 86.6 ± 2.7 in left knee patients at 6-month and 1-year after surgery. There was a correlation between shifting degree of GCP and changing degree of HSS score 6-month and 1-year after surgery (r=0.424 and 0.139). As recovering of the joint function, the weight on operated limb could be increased, thus the GCP moves from its initial position to the operative side after TKA. While, the shifting degree of GCP can be a reflection of recovering of the joint function in some extent.